1. Field of This Invention
This invention relates to a process for the in-vitro biosynthesis of hormones, especially of insulin, by in-vitro conservation or in-vitro propagation of cells from organs and tissues of animal or human origin under suitable conditions for cell growth and cell conservation, and isolation of the formed substances in a known manner from the culture medium or by the processing of the cells.
2. Prior Art
High value natural substances of animal or human origin, for example, insulin or other hormones, nowdays fulfill important tasks in medicine and biochemistry. Here one is mostly dealing with substances which heretofor could not be produced chemically or could be produced only with the utmost difficulty. At the present time, the tissue or body fluids of animals serve almost exclusively as raw materials for the production of such expensive substances. Since the product that is to be obtained is often contained in only a small portion of the cells of the tissues to be processed, there is always a high ballast (amount) of unspecific, unwanted material. In the future, additional problems will be present in the procurement of the raw material.
Furthermore, it will be absolutely necessary for reasons of the specificity of the species to reach back, at least partially, for materials of human origin since corresponding products obtained from animal material have too low of an effectiveness (efficacy) or no effectiveness at all. As far as one is dealing here with tissues, the required material is only available in insufficient quantities and mostly in unsatisfactory condition. Therefore, it is still unavoidable in most cases to escape the need to resort to the use of animal material.
Up to this point in time, suitable and generally applicable processes for cultures for mass propagation of cells are still lacking. One must consider that the cultivated cells adapt themselves to the empirically composed culture medium and must build up at least a microenvironment with relatively favorable growth conditions. In the case of the "surface" process such is possible in principle, however, the yield of cells is low since the cells have only two dimensional growth. In the case of the "suspension" process, such microenvironment is constantly disturbed by the changing contact (interface) with the culture medium. In addition, such process could be used hitherto only for a few type of cells.
German OS No. 2,431,450 teaches a process for the in-vitro propagation or in-vitro conservation of cells which is carried out using hollow fiber diaphragms. Such process, however, has the disadvantage that any build-up (scale up) of a technical (industrial) system is not practical.
The known culture processes furthermore mostly lead to "de-differentiation" and thus to a more or less quick loss of the specific synthesis functions of the cells. The de-differentiation, however, is not a process inherent in cells--it is caused in the first place by insufficient culture conditions.
Another disadvantage of the known culture processes is the high costs for the culture medium, which are caused by having to add up to 90 percent of blood serum. Customarily 10 percent of blood serum must be added to the culture medium.